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Latin

Noun

Related terms

Crux (, lang-la cross), commonly known as the
Southern Cross (Crux Australis, in contrast to the Northern
Cross), is
the smallest of the 88 modern constellations, but
nevertheless one of the most distinctive. It is surrounded on three
sides by the constellation Centaurus, and to
the south lies Musca. Ancient
Greeks
originally considered Crux to be part of Centaurus; however, the
precession of the equinoxes gradually lowered these stars below
the European
horizon, and they were eventually forgotten. (At the latitude of
Athens in
1000 B.C., Crux was clearly visible, though low in the sky; by 400
A.D., most of the constellation never rose above the horizon for
Athenians. ).

Notable features

With the lack of a significant pole star in
the southern
sky (Sigma
Octantis is closest to the pole, but is too faint to be useful
for the purpose), two of the stars of Crux (Alpha and Gamma,
Acrux and
Gacrux
respectively) are commonly used to mark south. Following the line
defined by the two stars for approximately 4.5 times the distance
between them leads to a point close to the Southern Celestial
Pole.

Alternatively, if a line is constructed
perpendicularly between Alpha Centauri and Beta Centauri, the point
where the above line and this line intersect marks the Southern
Celestial Pole. The two stars are often referred to as the "Pointer
Stars" or "White Pointers", allowing people to easily find the top
of Crux.

Contrary to popular belief, Crux is not opposite
to Ursa
Major. In fact, in tropical regions both Crux (low in the
south) and Ursa Major (low in the north) can be seen in the sky
from April to June. Crux is exactly opposite to Cassiopeia
on the celestial sphere, and therefore it cannot be in the sky with
the latter at the same time. For locations south of 34°S, Crux is
circumpolar and thus always visible in the night sky.

Crux is sometimes confused with the nearby
False Cross by stargazers. The Southern Cross is somewhat
kite-shaped,
and it has a fifth star (ε Crucis). The False Cross is diamond-shaped, somewhat dimmer
on average, and does not have a fifth star.

Other names for Crux

The Māori name for
Crux is "Te Punga" - "the anchor". It is thought of as
anchor of Tama-rereti's waka (the
Milky
Way), where the Pointers are its rope.

In Tonga
it is known as Toloa — duck; it is a duck flying over, heading
south, and one of his wings (δ) is wounded because Ongo tangata — 2
men — α and Β Centauri threw a stone at it. The Coalsack is known
as Humu — triggerfish, because of its shape.